I. Field of the Invention
The present invention relates to an optical signal processor and to a method of processing optical data.
II. Prior Art and Other Considerations
In communication systems spread spectrum techniques have been used and it is though that such techniques could offer several advantages in local area networks. In particular, spread spectrum optical communication techniques based on white light interference have been known for some time and recently these techniques have been used in coherence multiplexed optical fibre sensor systems.
Recently a spread spectrum technique, referred to as code division multiple access (CDMA) has been described for use with local area networks. In this scheme each user is assigned orthogonal codes, which results in a substantial increase of the bandwidth of the transmitted signal. However, the bandwidth requirements of this technique can only be supported by wide bandwidth channels such as a occur in fibre-optics, as well as requiring wide bandwidth signal processors at the receiver. Conventional receivers for CDMA use electronic processors, however, these are slow when compared with optical systems and also can be effected by electrical noise. It is desirable to provide an all-fibre and integrated optical processor which could facilitate and permit all optical processing so that maximum potential of such techniques can be realised.